Many processes are known for sorting and separating material. These processes are often mechanical in nature and performed by an automated machine or apparatus that is controlled by a computer. These sorting machines, or portions thereof, can experience wear attendant to contact with associated material during sorting operations. Often these parts are made from stainless steel and can have service lives of up to one year depending on thickness. Wear tiles are often applied to these steel portions of the machines that are subject to such wear in order to extend the working life of the parts and the machine as a whole. The wear tile is used as a barrier between the associated material and the machine parts so that the wear tile itself is worn away, rather than the machine parts being worn.
The material to be sorted is normally separated into two or more groups. These groups can include for example, a group of material that is acceptable or desired for use or consumption (i.e., desired product), and a group that is not acceptable or undesired for use or consumption (i.e., undesired product).
Various characteristics or properties of the material are used as the basis for separating the material into these groups. Parameters are established for sorting out undesired material from desired material based on the properties being monitored. Often, optical and/or physical properties of the material are monitored and used as the basis for separation. In these cases, material is normally sorted with optical scanning systems that employ cameras, lights, and sensors of various kinds to monitor or detect certain properties of the material for example, size, color, transparency or opacity, reflectivity, infra-red absorption/reflectivity, combinations thereof, and the like.
If wear tiles are introduced into a sorting machine, the wear tiles, or portions thereof may chip from the wear tiles during sorting operations and inadvertently mix with the material to be sorted. Standard wear tiles used in sorting machines are various shades of white resulting from the material components used to form the tiles. When used in machines using optical sorters for the separation of food products such as white rice, for example, white wear tiles are inadequate. White wear tiles do not exhibit optical properties sufficiently different from the optical properties of the white rice—or other material with shades of white—in order to allow the optical scanning system to separate chipped white wear tile from the desired product.